In semiconductor fabrication it is desirable to employ automated handling on the semiconductor wafers for efficient processing. Said wafers are typically retrieved from and loaded back into a carrier holding a number of wafers. The space available between adjacent wafers in the carrier is very small.
Insofar any handling apparatus must be constructed with a flat and elongated equipment (tool) to be fed in or retracted from said carrier.
At the same time, while the wafers being moved, the wafers must be held securely, but gently and are not allowed to interfere with adjacent wafers in the cassette (carrier). Any contact with the surfaces of the wafers should be avoided.
An apparatus with piezoelectric grippers is known from EP 0 810 636 A2.
EP 0 778 611 A2 discloses an end effector for a wafer transfer device, comprising a pocket allowing the end effector to contact only the edges of the wafer.
U.S. Pat. No. 4,118,058 discloses a tool for the contact-free support of discs by gas streams impinging on the discs when emerging from the supporting face of the tool at an acute angle to the disc surface.
A disadvantage of the known tool is based on the fact that especially thin wafers are deformed during transport.
The same is true with respect to the pick-up device for lifting and moving semiconductor wafers according to U.S. Pat. No. 4,002,254. The pick-up device has a working member, the underside of which forms a flat suspension surface incorporating the orifice of a single inclined jet through which air is ejected in an unbalanced flow towards a limiting surface at one end of the suspension surface.